Electric liquid heater



W. A. ANDREWS.

ELECTRIC LlQUlD HEATER. APPLICATION FILED MAR. 11. 1920.

1,405,475, Patented Feb. 7, 1922.

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ELECTRIC LIQUID IIE ATER.

Specification of Letters'Pa'tent.

Patented Feb: 7, 1922.

Application filed Email, 1920'. Serial No. 365,107.

To allwk'om ifmay concern;

Be it known that I, WILLIAMLAL ANDREWS, a citizen of the Unitedstates of America, residing at Detroit, in the county of lVayne and State of Michigan, ha-ve'inven'te'd certain new and useful Improvements in Electric Liquid Heaters, of which the following is a specification, reference being bad therein to the accompanying drawings;

This invention relates to electric liquid heaters and relates "more 'particularlyto apparatus for electrically heating water;

It isthe object of'the" invention to provide an apparatus for' heating water and other liquids adapted to employ the liquid to be heated as a resistor element of theheater;

A further object is to provide a convenient adjusting means for-regulating the amount of water functioning asa'res'istor in a heater of the above defined type.

In the drawings:

Figure 1 ,is a view in side elevation of the improved heater installedin a watertank or boiler;

Figure 2 is an end view of the electrodes of the heater and their mounting;

Figure 3 is a view similar to view 2 but showing a modified form of the invention.

In these views A and A respectively designate two rectangular insulating plates formed preferably of mica or porcelain, said plates being secured together at their corners by bolts B and being maintained in an accurately parallel spaced relation by spacer sleeves C upon said bolts. Preferably, said plates are mounted vertically and are secured at their lower ends, respectively, to a pair of angle bars D. Upon the opposing faces of said plates there are mounted in registering relation two copper plates E and E, a considerable margin being left between the peripheries of said plates and those of the insulating supporting plates A and A. To said plates there are preferably respectively connected the leads F and F of any suitable energizing circuit. Between the plates E and E there is arranged a pair of glass plates G and G which are parallel to said plates E and E and are adjustable to and from each other, so as to occupy either an edgewise abutting relation or be spaced various distances apart. As a provision for relatively adjusting the plates G and G preferably there are mounted upon the remote edges of said plates a pair of nuts H .electrodes formed by with which are1espectivelyengaged differentially threaded extremities of a rod I rotatable to effect a movement of thenuts H and attached'plat'es G and G to or from each other. As shown in F 1 the describe'd'liquidheater is mounted'in' a water tank J and the rod I passes through a wall ofsaid tank and is journaled in a packed bearing 'K in said wall, gearing L being provided exteriorly of the tank for actuating said rod. Also in said figure the angle bars D are shown as having the vertical flanges attheir end portions cut away and said end portions clamped between the flanges J formed respectively upon the side and bottom of the tank J.

In the operation of the described water heater when the circuit F, F, is energized the body of water intervening between the the copper plates E and E acts as a heating resistor to complete the circuit, said water rising as its temperature is raised and being replaced by colder waterfrom the bottom portion of the tank. The effective resistance of the water gap between electrodes E and E is increased by adjusting the glass plates G and G toward each other and when said plates are in contact the flow of current between the electrodes is reduced to substantially zero. When said glass plates are adjusted a maximum distance apart so as to be fully with drawn from between the electrodes E and E the resistance of the water gap is minimum. Thus, by properly adjusting said plates the resistance of the water gap may be so varied as to insure the desired heating effect.

In Figure 3 there is shown a somewhat modified form of the invention in which the resistance of the water gap is varied by increasing or decreasing the distance between two parallel electrodes forming plates M and M, the same being adjustable by means of screws 0 and O, which screws serve to conduct the current to said electrodes. By utilizing the liquid to be heated as the resistor element of the heater the invention accomplishes a considerable economy as compared to the usual type of electric heaters providing a coil or other metallic element as a resistor.

What I claim as my invention is: l -1. An electric liquid heater comprisinga pairof electrodes formed by spaced parallel re -mt plates, a pair of insulating plates arranged between said electrodes substantially in the and from each other to vary the water gap,

intervening between said plates and betwee the two electrodes. 7 i

w 2. An electric liquid heater comprising a pair of electrodes formed by spaced'parallel plates, a pair of insulating plates respectively having portions projecting between said electrodes, nuts mounted upon said insulating plates and a screw having differentially threaded'portions engaging said nuts for adjusting said plates to vary the water gap formed between said plates and between the electrodes.

3. An electric liquid'heater comprising a pair 0t electrodes adjustable'with reference to each other by meansof'a differentially threaded screw. i 4;. An electric liquid heater comprising a container, a pair of electrodes within said container adjustablewith reference to each other and means extendingthrough the wall of said container operable from without for relatively shifting said electrodes.

5. An electric liquid heater. comprising a container, a pair of electrodes formed by two parallel spaced plates within said container,

' means for maintaining a predetermined spaced relation between said plates and means extending through the wall of said containerfor relatively shitting said plates spaced parallel plates, a pair of insulating plates respectively having bars projecting between said electrodes, nuts mounted upon said insulating plates and, a screw having differentially threaded portions engaging said nuts for adjusting said plates to vary the water gap formed between said plates and between the electrodes operable from the outside of said container. r

8. An electric liquid heater comprising a pair of electrodes formed by spaced parallel plates, a pair of insulating plates arranged between said electrodes substantially in the same plane, said plates extending beyond the periphery of said electrodes, and means for relatively shitting said insulating plates to vary the water gap interveningbetween saidplates, and between the two electrodes. In testimony whereof I ailix'my signature.

WILLIAM A. ANDREWS. 

